This invention concerns the hearing aid in the preamble to Patent claim 1.
Hearing aids are used to equalize or compensate for hearing problems in a patient by processing acoustic signals picked up with a microphone that go through a receiver in the patient""s ear canal and are amplified or changed. An acoustic outlet hole is provided on the hearing aid through which the acoustic signals produced by the receiver are fed into the auditory canal.
It has long been known that the acoustic outlet hole is often reduced in size or even stopped up completely with deposits, so-called earwax. Moreover, these deposits spread out further into the inside of the hearing aid, and get into the inside of the receiver or the hole. The result of this is that the transmission properties of the hearing aid change. In addition, irreparable damage often occurs to the individual components of the hearing aid, and especially to the receiver itself.
A hearing aid is known from EP-0 377 074-A2 that has a receiver with two holes, where a first tubular canal leads from a hole in the receiver into the patient""s ear canal and a second tubular canal from the second hole in the receiver to the side of the hearing aid pointing to the outsidexe2x80x94the so-called face plate. The inside of the hearing aid has a chamber connecting the two holes, which is bounded on one side by a moving membrane, and the membrane can be deflected by a regulating unit to produce acoustic signals. Besides the chamber mentioned, there are two other chambers and holes in the housing of the hearing aid, through which a pressure difference produced by changes in height can be equalized between the ear canal and the atmosphere on the hearing aid. Such pressure-equalization devices are also called xe2x80x9cpressure ventxe2x80x9d devices.
According to the known theory, deposits that have settled over time, especially in the receiver or in the canal to the ear canal of the hearing-aid wearer, can be removed from the receiver and thus from the hearing aid by opening the hole in the face plate, which is closed during operation and by pushing a cleaning agent through the second canal, the receiver and finally the first canal with a spray or the like. In this way, all deposits can be flushed out. After the cleaning process, the hole in the face plate is closed again so thatxe2x80x94according to the known publicationxe2x80x94no unacceptable changes in transmission function can occur.
The problem of the invention is to specify a hearing aid that has a much simpler design compared to the known hearing aids, but is no in any way inferior to the known hearing aids in terms of function.
This problem is solved by the measures given in the characterizing part of Patent Claim 1. Advantageous variations of the invention are given in the other claims.
The invention has the following advantages: because a receiver with two-holes is used in the hearing aid, one hole of which is connected via a canal to the ear canal of the hearing-aid wearer and the other hole via another canal to the outside world, the hearing aid can be cleaned in the simplest way, for example by blowing it out. At the same time, the canals also serve as a pressure vent, with no unacceptable change in the characteristic transmission function. The hearing aid in the invention also has the advantage that choosing the dimensions of the other canal can improve the transmission properties of the first canal in terms of conduction adjustment to avoid reflections.
The invention will be explained in greater detail below using the drawings as examples.